Liquid column level



March 30, 1948. l Q C; LEACH 2,438,758

LIQUID COLUMN LEVEL Filed Deo. 29, 1943 FIG.

FIG. 3.

INVENTOR CHARLES QLEACH A TORNEY Patented Mar. 3 0, 1948 corr-ies .6-Claims. t v1 TheV invention relates fto-levels ,tof-"the :type y:in which an elongated-flexible tube' has: separately movable vinstrumentsat its ends, thereifbeing a liquid iin the tube, and Ausually inthe linstruments also. The devicey employs;the tendencyfmffthe surface vof the :liquid at the ends eof the 2tube, y.or inthe instruments, 'to-seek arcommon level. If one instrument is raisedsor lowered relativertosthe other instrument, the lrise or fallv of theA liquid levelin the latteriinstrument,#relative 5to afgiven point, Willindicate tothe; observerwthe l.relative position of the other.instrument-*.and-.ofnthefsurfaces to which theinstruments varerapplied,

One object ofthe invention .is .to facilitate the use` of :such a, levelrfor measuringminutevaria tions 4virl-the vrelative height of spacedaobjectsforfof dilerent pointson the same object.

Another Objectis ,to avoid the necessityy :of: close observation or scrutiny of a portion of the -level to determine its reading. It is desired -toprovide the level with va readily observed'A signal, .audible or visible, Whichwill function under ajpredetermined condition.

Another object is toifacilitate the -use ofesuclra levelbyaperson Who is at-aposition relativelyremote from the rvends-of. the liquid-containingltube and the vinstruments associatedftherewith.

Other objectsare to avoid loss of the uidlandV to maintain the fluid in a compactconditionrand to provide for close adjustmentzof theextentiof the fluid throughout vthe-level.

These and other detail objects `ofthefinvention as Will appear from the following-description are attained by the structure illustrated lin the -accompanyngdrawings, in which- Figure lis Vvin part Van elevation f andfinwpartea section throughthelevel.

Figure 2 is a transverse sectiontaken on the line 2-2 of Figure l and drawn to an enlarged scale.

Figure 3 is anedge or end View. ofthe level.

instruments shown Figure 1 .anddrawn toan enlargedscale.

The leveliillustratedis particularly:adaptedfor use in ,determiningfthe relativeheight of `Widely spaced points such, for example, rasthe. opposite ends ofa lathe or planer .bed criofjspacedlpoints on an airplane Wing or frame or of ajig or toolfor use in connection with the same.

In one4 'convenient arrangement, the structure comprises a .platform Ii mountedaon lcastors or rollers 2`and ,having an upstanding frame 3 and carrying theiiiexibleA tube'fl atta'chediatits endsato instruments 5 and which may bemountedupon bracketsl onframe 3 or may behandledjbythe 40. Figure 4 is a vertical section throughone ,of .thev

1 overaaiiortor'aidesiredllocation and''the instruments 5#andf'fmayfbe'lftedf'frombrackets 1- and applied .toisurfacestheh'eightl'o'fwhich relative to eaehiothen 'is :toi bei determined. y For example, it may '.be`-:de`sired: todetermine' the :flatness l or 4relativeheights of spacedapointsonfaflarge surface plate such iaslfiis'-1used: :inzfmachin-e `shops for like places ,.:to 'flayfoutz centers,- shoulders and :other points omdiesand jigs; zSuch azplate isindicated at-:Bfantazthe -finstrumentsr25and 6 are shown ap pliedi'ttotazplate .Bithrough a -micrometer 'Quand ya micrometerirod'flll respectively. A

A panel ll is slidably mounted-on frame'f3'and adjustablyaretainedsainriplacez bvr'studs-` Withwing nuts vft2; "The:intermediatenportion o'fi:tube .'41 is carried; on panelfjlcle'andtmaytbe fraised or lowered therewithronfframe. 31toaccommodate:different conditionsiotuse oftheil'evel.'

Preferably .the'body offeach .instrument..` 5i and 611s ofi rigid metal-:and: includeszafbase .il-23:, lone 2 or merel-t.umtandingwalls`v IAB. and a cap l5.. `One end'znf: tubefhlf'i i secured tor-base zl. :A .cup-like member: 6, fof...p1astic.ornother yelectrically insulated material, is seated onhase I3,';and;a sleeve Gazinsertedaat'fone end: into ztube; 42pmjects atfits otherrendtfinto' theginteriorroffcup-il 6.

o'liube` 4wanclwxzup.fll' are: supplied: `With liquid mercurmasiindicated at ll'l. v,-1`heinsidefof cup l5 iszsshoulderedeat 18: Itoaform fra; stop limiting '-.the downward movement/o'fiaI disc I9, apertured at its center, Whichmormallyffloatsiony the surface vof the n'iercury.y A closure: 20 iszapplied to-cup llirand anlannular; nut `:2| .''threadedin side Wall 114,:thrusts theaclosurezfagainst the cup and `-theicup 'f against basefil: .:Amontantscrew 22,'- threaded l through closure-'f2 hasza'gpointzprojecting -below theolosureini'lnea-.withgtheaperture;in'disc ilSa-nd a head projecting `vnabeve e .the :.fclosure. A downwardly opening housingsl is.,.thrust-.against: cap' |15 by-an annular nut 24. A lamp 25is1supportedfthrough itsstcentral .electrodei-Q-i frestingfon screvvl 4221,and proectsaupvvardly into ifhousing 23 andv is .held againstgplay within; the housing by a-springy 21 compressed betweensthe flipper fend. of.v` therflamp andI the-opposing `endfoftfthehousing. A `relativelyelight spring 2.8:*surrounds .contact screw 'i 22 and-s bears .against Vthe. :annular electrode on :the 1amp,-. surroundingelectrode 16, Vand arcooperating shoulder formed on nut 2 I.

- .,CupJ, closurefzmand housing-.23 arancia-conductive bf.. electricity. rand.,-housing l 23 ,is ltransciation of the lamp and the device 29, 30 enables the operator tov readily observe simultaneously the perpendicularity of `the instrument at the same time that he observes the height of the instrument, relative to the other instrument,`

Without shifting his glance.

Screw 22 and the liquid mercury compriseV I means for making and breaking an electric cirl cuit, of which they form parts, which includes the lamp electrodes, spring 28, nut 2|, wall I4, base I3 and the metal braidv3I about tube 4.

A Vent 32 in closure 20 leads from the interior of cup I6 to the atmosphere to avoid air pressureinterference with the rise and fall of the mercury in the cup to thefextent necessary to make andV break the circuit. If the mercury rises substantially above the lower .endof screw 22, :disc I9 will seat against the, bottom of vclosure 20, sealing vent 32. This arrangementwill prevent the escape of 'mercurythroughthe vent if the instrument is lowered' substantially below' the height of the instrument at'theother end of the tube or if the instrument is inverted. The upper face of the mercury column will be convex due to the surface tension of the mercury vand there will be no leakage of the mercury aroundthe edge of the disc prior to the closure ofthe vent. Also the convex face of the mercury column'tends to center disc I9 axially of the cup and maintain the alignment of the hole in the disc and the point of the contact 22.

The intermediate portion of tube 4 is provided with a member 34 mounted on panel II and including'a valve 35 and a reservoir 36. When the y level is Yconstructed,'mercury is suppliedto reservoir 36, tube 4 and the instruments through valve 35 and, to facilitate this operation, an exhaust pump hose 31 may be connected to vents 32. A

plunger 38 is adjustably mounted on member34,l

projecting into reservoir 36, and providing means for minutely controlling the .volume of mercury in the tube and in cups I6. Y

A vibrator 39 on panelv II is arranged to contact the wall of reservoir 36, and theivibrationsl of this device transmitted tothe mercury column promotes prompt :dow of the mercury when either instrument or 6 is elevated and therefore makes the level more responsive to slight variations in the relative positions of the instruments.-

Preferably a lamp 40 is' placed in a circuit common to both lamps -and Will light "when either of lamps 25 is lit. Also an extension cord 4I to a lamp 42 may be plugged into a jack 43 on panel Il and may be handled by theoperator to hold alongside of one of the instruments 5 or 6 for use in determining the action of the light on the other instrument when the latter may be out of range of vision. 'Y y The electric circuits of the device are dia grammatically illustrated in Figure 1 and are energized by a cord C which may be attached to the usual 110V-volt outlet. Preferably the lamps' are in a circuit energized from thefl'lO-volt cir cuit by a transformer T. The use of the trans'- former eliminates the possibility of shock to theA user from portions of the level which the circuit.

For accurate Work, a micrometer ilV and ,micrometer rod lareapplied tothe instruments 5 are part of 4 and 6 respectively, one or more adjusting washers 45 being used if desired, and the instruments are placed close together on a known level surface. The micrometer is turned down, lowering instrument 5 so that the mercury rises therein, until the light is on in instrument 5, indicating that it is at a lower height than instrument 6. The micrometer is then turned up until the light goes off and the micrometer reading is noted. The micrometer is turned up further until the light goes on in the other instrumentI and the micrometer readingis noted. The dierential in the readings may be increased or decreased by adjusting the volume control plunger 38 so that both signals will be out during a known few thousandths of an inch. The level may then be used todetermine the relative height of surfaces to whichthe instruments are applied, although the :surfaces are far apart. For example, the level has been constructed and used satisfactorily for this purpose in application to points'spacedY approximately thirty feet from each other.

If such iine degree of accuracy is not needed, flat or round rod scales may be, applied to the instrumentsQas indicated in VFigure v2, wherethe wall I4 of the instrument isA shouldered at 46 Vto receive a clamp 41 by which a scale 48 may be secured to the instrument or al V groove 43mm be formed in wall I4 to accommodate a measuring rod 50 which may be securedL tothe 'instrument by `a clamp (not shown) similar to clamp 41 and seated against shoulders 5I. A i j Instead of the lamps lighting when 'the instruments are at diierent levels, theY height of the mercury in both cups I6 wmay be raised byadjusting plunger 38 untilboth lights are lit when the instruments are at the same level and one of the'lights will go out when the associated in.- strument is raised above the level, of V theohther instrument. c

While the use |of the plural instruments -atop;

posite ends of the tube is preferred, oneend of the tube could be permanently secured at auxed height and a circuit making and breaking instrument applied to the other endof the tubel only,

whereupon the heightrc'fv an objectto which the instrument is appliedcould be determined rela tively to the single known helghtoflthelfxed end'of thetube. l ,f

It is within the scope of the invention to substitute an audible signal foreach lamp ,25,7 40 or 42, it being understood thatA in the broader form the invention is applicable to ranyQarrangementV A spirit level may bersubstituted for the ball andvsocket level indicated at 29, 30 without affecting the operation of the instrument.

The embodiment of the invention may be varied substantiallyfrom the above specific description and corresponding.illustration in other ways than here indicated and the exclusiveY use of those modifications coming within-the scope of the claims is contemplated.y

What is claimed is: f

1. In a level comprising independently mov-v able instruments connected byv an elongated ilexible tube containing liquid andl a. signal device actuated by the height ofthe liquid incne of the instruments, means arranged to jar the liquid topromote the readyiiow of the liquid injsaidin-` strument.

2. In a level, independently movable instruments, an elongated iiexible tube connecting said instruments and containing metal in liquid form, a signal device in one of the instruments actuated by an electric circuit of which said metal forms a part and closed by an increase in the height of the metal in said instrument, and a vibrator arranged to jar the metal and thereby maintain it in a compact condition.

3. A level comprising independently movable instruments, a flexible tube connecting them, a liquid in the tube, an electric circuit comprising the liquid and an element along the tube and means for closing the same when the liquid level in one of the instruments rises above a predetermined point, and a lamp lit by the closing of said circuit.

4. In a level, an elongated Iiexible tube lcontaining a liquid, and an instrument at one end of the tube provided with a liquid-receiving chamber open to the tube and having an air vent above the normal level of the liquid in the chamber, there being an electric circuit formed by the liquid and by the exterior of the tube and closed by the movement of the liquid to a predetermined point, a signal device actuated by the closing of the circuit, a float in the chamber and supported on the liquid therein and operative upon the movement of the liquid, prior to the latters reaching said point, to close said vent.

5. In a level, an instrument including a chamber substantially but not completely filled with liquid, an elongated iiexible tube having a terminal portion extending Well into said chamber and opening thereto at a point spaced substantially from the chamber walls and immersed in the liquid irrespective of the position of the in- 6 strument, a float resting on the liquid in said chamber, an air vent from said chamber at a point above the normal level of liquid therein and adapted to be closed by said oat as the liquid rises, there being an electric circuit closed by the rise of the liquid prior to the closing of said vent, and a signal device actuated by the closing of the circuit.

6. In a level of the class described, spaced instruments movable independently of each other, and a flexible tube connecting them and containing liquid, signal devices in said instruments aotuated by the relative rise and fall of the liquid in the instruments, at least one of the instruments having upwardly and downwardly facing fixed seats arranged for selectively mounting a micrometer.

CHARLES C. LEACH.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 318,885 Espenshied May 26, 1885 397,294 Karr Feb. 5 1889 872,183 Jenning Nov. 26, 1907 986,109 Weymouth Mar. 7, 1911 1,375,278 Clayton Apr. 19, 1921 1,907,402 Fidor May 2, 1933 FOREIGN PATENTS Number Country Date 3,252 Great Britain 1881 364,591 Germany 1923 635,090 Germany 1936 

